This headstamp, M.8, on 8x50R rounds and clips is described in the White
M.8 1937 and of manufacturing Hirtenberger for Italy.
I agree with pierre jean
take a look here
“M” probably stands for “Mannlicher” since Hirtemberger also loaded 8 x 50R Lebel ammunition simply headstamped with a star and date
I also think that the “M” on your Mauser clip could stand for “Mauser”,but I don’t know the maker
Thank you pierre-jean. What book is that page from? I’ll have to try and get one.
Thanks Pivi for the link.